The subject invention relates to lactone derived resins. More particularly, the invention relates to lactone derived resins which are UV curable and are useful as coating compositions.
Many useful polymeric coating compositions are known. Such compositions are conventionally applied from a liquid solution onto the substrate and thereafter cured to form a polymerized coating. The coating compositions generally contain an organic solvent. The solvent is removed after the coating composition is applied thereby leaving a deposit of the polymeric solids on the substrate. An elevated temperature is often used to drive off the organic solvent. In recent years, there has been concern about the possible environmental pollution and energy waste caused by organic solvents. Elaborate recovery systems can be used to recover most of the organic solvents driven from the coating compositions upon curing: however, these recovery methods generally are rather expensive to install and themselves are energy consuming.
One area of coating technology which has received considerable interest in recent years has been the formulation of high solids coating compositions. Such compositions can contain 100 percent solids, thereby eliminating the need for and concern with organic solvents. These coating compositions can be cured by conventional thermal means. The problems with most of the high solids coating compositions are that they are often too viscous to use or do not cure rapidly enough for most commercial applications.
A number of different UV curable coating compositions have been suggested for use. These compositions typically contain near 100 percent solids and are cured by the use of UV light. However, as with the high solids coating compositions, the prior art UV curable coating compositions are also often quite high in viscosity and therefore difficult to apply using normal coating techniques.
There has now been found coating compositions which have low viscosity and can be applied under normal coating conditions using conventional techniques. The compositions are used for in-mold coating operations as well as for operations where an UV-cure is desirable. The cured coatings are abrasion resistant and flexible.
As used herein, all percents and ratios are by weight unless otherwise indicated.